The present invention relates to a device for the non-destructive examination of heterogeneous samples by analysis of the Raman radiations scatter by said samples.
The study of heterogeneous samples is a constant source of interest of the physicist or technician seeking to discover the nature and structure of certain bodies. Examination is already effected by the microscope, in particular the electronic probing by the spectroscopy of emissions by lasers. However, facilities are never sufficient for the research worker.
The device according to the invention provides a new way of studying bodies by using light scattering physical-phenomena known as the Raman effect.
Microscopy is already known where the photons of a radiation are sent onto a substance. This radiation is then absorbed and converted and it is re-emitted at a higher wave length that may be analysed under a microscope and which reflects the nature of the surface studied. The microscope used is sensitive to the re-emitted light at its wave length of re-emission. However, examination by this microscope often needs to be completed by another examination.
Electronic micro-probing is also known, which has been hinted at above. This process permits only a very local observation of the matter.
Radiation is also known, produced by a light amplifier by stimulated emission of electromagnetic radiation which produces a high intensity light source of coherent light, called a "laser". Laser radiation has been applied to a process of studing surfaces, which consists in sending its radiation so that it vaporises the substance, of which the vapours may be analysed by spectroscopy.
The drawback of this process is that it destroys the matter, at least locally.
Electronic scanning techniques are also known, which are widely used in television. Instead of scanning a fixed surface by a rapidly moving beam of radiations, the beam may also be fixed and the surface to be explored may move along the abscissa and, by shifting slightly each time, along the ordinates, to effect a similar scanning.
In optics, slotted monochromators are also known which select the radiation received and furnish a monochromatic radiation. Radiation detectors are also known which may be of the photomultiplier type to be able to obtain signals that may be amplified by the known electronic techniques, particularly for cathode tubes restoring a visible image directly or to constitute recordings which may be used subsequently. Laser Ram an spectroscopy, utilizing Raman scattering for the qualitative and quantitative chemical analysis of samples, also is known. Raman spectrometers have proven to be valuable laboratory tools for identifying and recording Raman spectra in connection with the investigation of the molecular properties of matter.